The present invention relates to a fan unit and a heat-emitting element cooling apparatus which uses the fan unit, for cooling a heat emitting element such as an electronic component.
Such a heat-emitting element cooling apparatus has been known that includes a heat sink having a base and a plurality of radiation fins, and a fan unit. In this apparatus, a heat-emitting element to be cooled is mounted on the rear surface of the base, and the radiation fins are fixed to the base. The fan unit is disposed over the heat sink, for blowing air along one or more the radiation fins to promote heat dissipation from the radiation fins. In this heat-emitting element cooling apparatus, heat generated from the heat-emitting element is transferred from the base to the radiation fins. Then, the air flowing from the fan unit along the radiation fins carries away the heat of the radiation fins, thereby cooling the heat-emitting element.
U.S. Pat. No. 6,407,913 and U.S. Pat. No. 6,621,699, for example, disclose electronic component cooling apparatuses in each of which a heat sink provided with a plurality of radiation fins juxtaposed on a base, is cooled by a fan unit. In these units, the fan unit is mounted on the heat sink through mounting engaging structures. Further, a plurality of lead wires are arranged along one of webs coupling motor supporting means for supporting a motor to a fan casing.
U.S. Pat. No. 6,671,172 discloses an electronic component cooling apparatus including a plurality of radiation fins that extend radially in the radial direction of a base with respect to the base that extends in the axial direction of a revolving shaft of a fan unit. Air flow passages formed between two adjacent radiation fins of the radiation fins are open toward both of the axial directions and toward the radially outward direction. This publication also discloses a structure in which each of four engaging sections that extend from the fan casing of the fan unit is inserted into each of the air flow passages formed between the two adjacent radiation fins of a heat sink, thereby preventing the fan casing from rotating with respect to the heat sink. Still further, the radiation fins disclosed in this publication are curved in one of the peripheral directions of the revolving shaft, and air supplied from the fan unit rotates in a direction opposite to the direction in which the radiation fins are curved.
FIG. 3 of U.S. Pat. No. 6,480,383 discloses a technique by which a plurality of projections provided for a fan casing is inserted into air flow passages each formed between two adjacent radiation fins of a plurality of radiation fins, thereby preventing the fan casing from being disengaged from the heat sink.
USPAP No. 2002/0075649 discloses a structure in which a plurality of mounting engaged sections is provided in a plurality of radiation fins, and a plurality of mounting engaging sections provided on a fan casing of a fan unit engages the mounting engaged sections, thereby mounting the fan unit on a heat sink. The mounting engaged sections disclosed in this publication are respectively constituted by notches formed at ends of a part of the radiation fins in their radially outward direction. Hooks for engaging the notches are integrally provided on the mounting engaging sections on the fan casing.
Further, Japanese Patent Application Laid-Open Publication No. 280780/2002 discloses an integrated circuit cooling unit in which in order to mount a fan unit on a heat sink, grooves for partially receiving a plurality of lead wires that extend from the fan unit are formed in a fan holder attached to a heat sink, thereby preventing the lead wires from coming out of the fan holder.
In the cooling unit disclosed in Japanese Patent Application Laid-Open Publication No. 280780/2002, the lead wires are fitted into the grooves arranged in the fan holder for mounting the fan unit on the heat sink. For this reason, when the fan unit is conveyed discretely, the lead wires need to be bent a plurality of times and bound together by a string, a rubber band, or the like. In the configuration disclosed in this publication, the lead wires are bent so that they meander along the side wall of the fan holder. The work of bending the lead wires so that they meander the side wall of the fan holder is difficult, so that the work becomes time-consuming unless it is accustomed to be done. Further, if the lead wires are bent at short intervals, an undue force will be applied to the lead wires or great deformation will be caused in the lead wires. Then, a lead wire disconnection may be generated. Further, when the length of the lead wires in this configuration becomes too long, the lead wires cannot be held by the fan holder without becoming an obstacle.